Punch presses are typically configured to hold a plurality of tools for forming a variety of shapes and sizes of indentations and/or holes in sheet workpieces, for example, sheet metal. Tools of this sort commonly include at least one punch assembly and corresponding die. For example, in a multiple station turret punch press, a rotatable turret includes a plurality of bores, which hold a corresponding plurality of punch assemblies above a workpiece support surface, and a corresponding plurality of die receiving frames are located below the workpiece support surface. Alternatively, in other presses (such as Trumpf style presses), a rail (instead of a turret) is used for holding the punch assemblies.
A conventional punch assembly typically includes a punch guide, a punch body or holder, and a punch. The punch may be either fixedly or releasably attached to the holder. The punch holder and punch are often slidably engaged within the punch guide for reciprocal, axial movement along a central longitudinal axis of the punch guide. When such a punch assembly, and a corresponding die, are mounted in a press and located in a working position of the press, beneath the ram (or integrally connected to the ram), the punch is driven out from the punch guide, through an opening in a stripper plate, in order to form an indentation or a hole through a sheet workpiece with the tip of the punch. The stripper plate, which is attached to an end of the punch guide, prevents the workpiece from following the punch, upon its retraction back into the punch guide.
Those skilled in the art appreciate that the punches used in punch assemblies require regular maintenance and modification. For example, the punches may need to be sharpened or replaced when becoming worn, may need to be replaced when a different punch shape (or footprint) is required, and/or may need to be adjusted in position within the assembly to account for different lengths thereof. A variety of punch assembly configurations, which facilitate these types of maintenance and modification, have been taught and, in some cases, commercialized; however, there remains a need for new punch assembly configurations and methods that increase the ease and the speed by which such maintenance/modification can be made.